This invention relates to triiodoisophthalic acid monoamino acid amides (amino acid derivatives of the acylamino-5-alkylcarbamoyl-2,4,6-triiodobenzoic acids), processes for the preparation thereof, and the use thereof as radiopaque agents, especially as X-ray contrast media for illustrating the urinary tract system, the cardiovascular system and the body cavities containing cerebro-spinal fluid.
3-ACYLAMINO-5-ALKYLCARBAMOYL-2,4,6-TRIIODOBENZOIC ACIDS ARE KNOWN FROM U.S. Pat. No. 3,145,197. Several amino acid derivatives of 3-acylamino-5-alkylcarbamoyl-2,4,6-triiodobenzoic acids have likewise been described, e.g., 5-acetamido-2,4,6-triiodoisophthaloyl digylcine in U.S. Pat. No. 3,102,880 and N-[3-N-(alkyl-acylamino)-5-alkylcarbamoyl-2,4,6-triiodobenzoyl]-amino acids in Helv. Chim. Acta 54 (8): 2551-2559 (1971). Although these compounds have a low toxicity, they have several undesirable side effects. For example, they do not meet the high requirements to be fulfilled by a medium for myelography, e.g., see Ugeskrift for laeger 134 (18): 936 (1972) and Advances in X-Ray Technology 115: 683-684 (1971). A primary requirement for radiopaque agents useful in myelography is the cisternal compatibility.